This invention relates to pneumatic deicers and more particularly to a pneumatic deicer and the method of making a pneumatic deicer of the type employing a boot of resilient material attached to the leading edge of an airfoil wherein the boot has a plurality of inflatable tubes which are selectively distended as by inflation pressure to break up ice accumulation which tends to form on the surface of the boot. The inflatable tubes are generally disposed in a direction parallel to each other in the spanwise direction of the leading edge of the airfoil. The tubes, however, may be disposed to extend in the direction of the airfoil or in any other angular position. The deicer is vulcanized by steam which also passes through the inflation tubes assuring that the tubular passageway remains open so that the inner peripheral surfaces of such passageway do not adhere to each other. The inflation of the tube is performed through a manifold that extends transversely of and overlies the tubes. In the manufacture of the boot assemblies, various modifications in tube construction have been tried to facilitate the inflating and evacuation process of the tubes since it is desirable to so construct the boot assembly to provide an unencumbered flow of air to and from the tubes. To insure such flow, additional materials, such as flocked liners or fabrics, have been integrated into the tube structure; however, such finally constructed boots would present ripples and objectionable thickness thereby rendering such boot objectionable for aesthetic reasons as well as for aerodynamic reasons.
The present invention provides a simple structure and method of constructing a deicer to provide for the adequate bleeding of the inflation tubes during the deflation cycle, eliminating the need for building in additional separating devices that add to the manufacturing cost and adversely affect aerodynamic conditions of the airfoils. The present invention substantially eliminates the causes of erosion of the skin of the deicers and materially improves the aerodynamics of the airfoils by keeping the airfoils smooth externally.